Radar observations of Venus at 3.6 centimeters

Radar Signatures of the Planets

“…The extremely low value of 1 per cent cross section reported by Karp et al (1964) a t 3.6 cm. wavelength seems difficult to accept.…”

Interferometric Investigations of The Atmosphere of Venus

“…The measurements are shown in Figure 1, which was taken from paper I. The marked decrease in the apparent reflectivity at short wavelengths was originally interpreted as atmospheric absorption by Karp et al [1964]. A full interpretation of these measurements is complex since the measured values depend on the atmospheric opacity, which is strongly wavelength dependent, and the• details of the radar backscattering law, which is at least slightly wavelength dependent.…”

Extraterrestrial Life

“…Perhaps new experimental tools being exploited in this laboratory (8) and elsewhere (9) will resolve the issue, or it may be that it will remain unsettled until the U.S. (or the U.S.S.R., whose interest in Venus appears greater than ours) performs such an experiment as the parachute-borne probe of the Cytherean atmosphere proposed by NASA.…”